Memory encoding in Alzheimer’s disease: an fMRI study of explicit and implicit memory

Alzheimer’s disease is the most common cause of dementia in older adults. Although the cognitive deficits and patho-logic hallmarks of Alzheimer’s disease have been well characterized, few functional imaging studies have exa-mined the functional competency of specific brain regions and their relationship to specific behavioural memory defi-cits in Alzheimer’s disease. We used functional MRI (fMRI) to examine seven early stage Alzheimer’s disease patients and seven healthy age-matched neurologically normal control subjects during intentional encoding of scenes. Subjects viewed blocks of novel scenes, repeated scenes or baseline. Data were analysed using whole-brain statistical parametric mapping and region of interest approaches. The Alzheimer’s disease group demonstrated impaired explicit recognition memory, but intact implici